PORT ST. LUCIE — Daniel Murphy has a strained right rib cage muscle and received a cortisone shot. Now comes the hard part for the Mets second baseman: not swinging a bat for at least a few days.

“I’m going to have to be smart,” Murphy said yesterday upon returning from New York, where he was examined by team doctors Tuesday.

David Wright and Scott Hairston incurred similar injuries last year for the Mets and missed significant chunks of spring training, but Murphy says he’s not thinking in those terms.

“Even if it were to take whatever it may be, we’ve still got plenty of time I think in spring training,” Murphy said. “The only thing I’m trying to think right now is I would rather miss spring training time than miss time in the season.”

“He said to just let the medication take its course,” Murphy said. “He said I’ll feel better in a couple of days, but I think it’s in our nature to want to know where it’s at and kind of want to twist on it. He said to just wait a couple of days, it will take, just trust it.”

* Frank Francisco is scheduled to begin throwing on Monday, according to pitching coach Dan Warthen. The right-hander has reported improved range of motion in his right elbow, which has been bothered by swelling.

* Collins plans to use Kirk Nieuwenhuis in the leadoff spot for Saturday’s Grapefruit League opener against the Nationals. Nieuwenhuis hit leadoff for a stretch last season.

“This guy played pretty well for us for eight weeks and I want to see him get some more at-bats,” Collins said. “When we were playing real well that guy was in center field, so he deserves the first shot.”

* Jenrry Mejia’s age and identity have been confirmed to be accurate, completing an investigation in the Dominican Republic that will allow the right-hander to receive a visa and report to camp within the next 1-2 days.